I. Field of the Invention
The present invention relates to certain alpha- and/or beta-substituted trifluoromethylketone compounds, their salts, hydrates and derivatives thereof, a process for their preparation, intermediates useful in their preparation, pharmaceutical compositions containing them and such ketone compounds as inhibitors of phospholipase A2 enzymes that are involved in the human inflammatory diseases and are thus useful agents in the treatment of inflammatory diseases such as asthma, arthritis, inflammatory bowel disease and neurodegenerative diseases.
II. Background of the Invention and Description of the Prior Art
Inflammatory diseases of the skin, such as psoriasis and atopic dermatitis, afflict greater than 5% of the population. And the inflammatory disease such as asthma affects more than 10 million people in US alone. Currently, the treatment of these disorders typically involves the use of topical and inhalation of coticosteroids and bronchodilators. However, these agents also have undesirable side effects such as skin atrophy which limit the duration of therapy. In addition, topical application of a drug is difficult for many patients where the affected area may be very large.
Phospholipase A2 (PLA2) is the common name for phosphatide 2-acylhydrolase which catalyzes the hydrolysis of the sn-2-acyl ester bond of phosphoglycerides and results in production of lysophospholipids and free fatty acids. When the fatty acid is arachidonic acid, further action by cyclooxygenase and 5-lipoxygenase enzymes results in eicosanoid production, which is implicated in inflammation, and leukotrienes which are linked to asthma. Lysophophospholipid metabolism results in production of platelet activating factor and both lysophospholipids and platelet activating factor also play a role in inflammation.
PLA2 enzymes exist as secreted forms (MWxcx9c12,000-15,000) and cytosolic forms (MWxcx9c85,000). The cytosolic or cPLA2 enzymes appear to play a key role in the pathway leading to the formation of platelet activating factor and the eicosanoids.
Inappropriate activation of the cytosolic PLA2 enzymes, therefore, can result in a variety of chronic and acute conditions including asthma, cerebral ischemia [Clemens et al., Stroke, 1996, 27: 527-535], Alzheimer""s Disease [Stephenson et al., Neurobiology of Stroke, 1996, 3: 51-63 and see also U.S. Pat. No. 5,478,857], rheumatoid arthritis, neutrophil and platelet activation [Huang et al., Mediators of Inflammation, 1994, 3: 307-308], chronic skin inflammation and damage to the skin resulting from exposure to ultraviolet light [Gresham et al., American Journal of Physiology, 1996, 270; Cell Physiology, 39:C1037-C1050] and macrophage activation [Balsinde et al., Journal of Biological Chemistry, 1996, 271: 6758-6765].
Inhibitors of the cPLA2 enzymes may, therefore, be of use in controlling a wide variety of inflammatory diseases. The literature describes a significant number of compounds said to be phospholipase A2 inhibitors.
Biochemistry, 1993, 32: 5935-5940, discloses a trifluoromethyl ketone analog of arachidonic acid having the formula 
as a selective inhibitor of cPLA2.
Bioorganic Med. Chem. Lett., 1995, 5: 519-522, discloses selective cPLA2 inhibitors of the formula 
where R is either H or OH.
Japanese published Patent Application JP09268153A (Derwent No. 97-554679/51) discloses cPLA2 inhibitors of the formula RCOCF3 where RCO is an acyl residue of an n-3 series highly unsaturated fatty acid. The compounds are said to be useful as antiinflammatory or antiallergic drugs.
Certain trifluoromethylketone have been disclosed as inhibitors of fatty acid amide hydrolase in Bioorg. and Med. Chem. Lett., 1999, 9: 265-270.
Published Application WO 98/25893 discloses arylsulfonamide compounds of the general formula 
wherein:
A represents a C4-C10 alkyl group, an aryl group, an arylalkyl group, radicals selected from the group consisting of xe2x80x94CHxe2x95x90CHxe2x80x94B, xe2x80x94Oxe2x80x94B, xe2x80x94Sxe2x80x94B, and xe2x80x94NHxe2x80x94B, or radicals of formula xe2x80x94CH2xe2x80x94X,
wherein:
B represents a non-aromatic C3-C8 carbocycle, a C3-C8 alkyl group, a heterocycle or an arylalkyl group, each of which is optionally substituted with one or more members independently selected from the group consisting of a halogen atom, a C1-C4 alkyl group, a C1-C4 alkoxy group, cyano, nitro, a heterocycle, an aryl group and an aryloxy group, and
X is a member selected from the group consisting of a halogen atom, xe2x80x94S-aryl, xe2x80x94S-heterocycle, and xe2x80x94PO3R2 wherein each R is independently selected from the group consisting of a hydrogen atom and C1-C3 alkyl;
R1 and R2 each independently represent a hydrogen atom, a lower alkyl group, or a group represented by the formula: xe2x80x94(CH2)qxe2x80x94Axe2x80x2 wherein q is an integer of 2 to 4, and Axe2x80x2 is a member selected from the group consisting of a hydroxyl group, a group represented by the formula: 
xe2x80x83wherein R5 and R6 each independently represent a hydrogen atom, a lower alkyl group, or a group represented by the formula: 
xe2x80x83wherein R7 represents a hydrogen atom, a lower alkyl group, or a group represented by the formula: 
xe2x80x83wherein s is an integer of 2 to 5; or
R1 and R2 each independently represent an unsubstituted cycloalkyl group, or a cycloalkyl substituted with a lower alkyl or halogen or condensed with an aromatic ring, a bicycloalkyl, or tricycloalkyl, said bicycloalkyl or tricycloalkyl being an aliphatic saturated hydrocarbon group made of two or three rings, respectively, with at least two carbon atoms being common to each ring, or an azabicycloalkyl group which is a bicycloalkyl group as described above in which one carbon atom is replaced by a nitrogen atom or a group represented by the formula: 
xe2x80x83wherein g and h are each an integer of 1 to 4, and Bxe2x80x2 stands for a lower alkyl group, an arylalkyl group, an arylalkyl group substituted by lower alkyl; halogen or a lower alkoxy group, or a pyridylalkyl group, or a pyridylalkyl group substituted with a lower alkyl group, a halogen or a lower alkoxy group; or
R1 and R2 may be combined together to form a 6- or 7-membered ring which may contain a nitrogen or oxygen atom in addition to the nitrogen atom to which R1 and R2 are bonded, and said 6- or 7-membered ring may be substituted with a lower alkyl, arylalkyl, cycloalkylalkyl or heteroarylalkyl group;
R3 represents a hydrogen atom, a lower alkyl group, or a C3-C8 cycloalkyl group;
R4 represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a halogen atom;
n is an integer of 1 to 4, provided that when n is 2, the two R4 groups may form a cyclohexenyl or phenyl ring together with two adjacent carbon atoms constituting the benzene ring; and any pharmacologically acceptable salts thereof as inhibitors of phospholipase A2 activity, particularly cPLA2.
Published Application WO 98/08818 discloses Inhibitors of phospholipase enzymes of formulae I, II and III 
or a pharmaceutically acceptable salt thereof, wherein:
A is independent of any other group and is selected from the group consisting of xe2x80x94CH2xe2x80x94 and xe2x80x94CH2xe2x80x94CH2xe2x80x94;
B is independent of any other group and is selected from the group consisting of xe2x80x94(CH2)nxe2x80x94, xe2x80x94(CH2O)nxe2x80x94, xe2x80x94(CH2S)nxe2x80x94, xe2x80x94(OCH2)nxe2x80x94, xe2x80x94(SCH2)nxe2x80x94, xe2x80x94(CHxe2x95x90CH)nxe2x80x94, xe2x80x94(Cxe2x89xa1C)nxe2x80x94, xe2x80x94CON(R6)xe2x80x94, xe2x80x94N(R6)COxe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94 and xe2x80x94N(R6)xe2x80x94;
R1 is independent of any other R group and is selected from the group consisting of xe2x80x94Xxe2x80x94R6, xe2x80x94H, xe2x80x94OHxe2x80x94, halogen, xe2x80x94CN, xe2x80x94NO2, C1-C5 alkyl, alkenyl, alkinyl, aryl and substituted aryl;
R2 is independent of any other R group and is selected from the group consisting of xe2x80x94H, xe2x80x94COOH, xe2x80x94COR5, xe2x80x94CONR5R6, xe2x80x94(CH2)nxe2x80x94Wxe2x80x94(CH2)mxe2x80x94Zxe2x80x94R5, xe2x80x94(CH2)nxe2x80x94Wxe2x80x94R5, xe2x80x94Zxe2x80x94R5, C1-C10 alkyl, alkenyl and substituted aryl;
R3 is independent of any other R group and is selected from the group consisting of xe2x80x94H, xe2x80x94COOH, xe2x80x94COR5, xe2x80x94CONR5R6, xe2x80x94(CH2)nxe2x80x94Wxe2x80x94(CH2)mxe2x80x94Zxe2x80x94R5, xe2x80x94(CH2)nxe2x80x94Wxe2x80x94R5, xe2x80x94Zxe2x80x94R5, C1-C10 alkyl, alkenyl and substituted aryl;
R4 is independent of any other R group and is selected from the group consisting of xe2x80x94H, xe2x80x94OH, OR6, SR6, xe2x80x94CN, xe2x80x94COR6, xe2x80x94NHR6, xe2x80x94COOH, xe2x80x94CONR6R7, xe2x80x94NO2, xe2x80x94CONHSO2R8, C1-C5 alkyl, alkenyl and substituted aryl;
R5 is independent of any other R group and is selected from the group consisting of xe2x80x94H, xe2x80x94OH, xe2x80x94O(CH2)nR6, xe2x80x94SR6, xe2x80x94CN, xe2x80x94COR6, xe2x80x94NHR6, xe2x80x94COOH, xe2x80x94NO2, xe2x80x94COOH, xe2x80x94CONR6R7, xe2x80x94CONHSO2R8, C1-C5 alkyl, alkenyl, alkinyl, aryl substituted aryl, xe2x80x94CF3, xe2x80x94CF2CF3 and 
R6 is independent of any other R group and is selected from the group consisting of xe2x80x94H, C1-C5 alkyl, alkenyl, alkinyl, aryl and substituted aryl;
R7 is independent of any other R group and is selected from the group consisting of xe2x80x94H, C1-C5 alkyl, alkenyl, alkinyl, aryl and substituted aryl;
R8 is independent of any other R group and is selected from the group consisting of C1-C3 alkyl, aryl and substituted aryl;
R9 is independent of any other R group and is selected from the group consisting of xe2x80x94H, xe2x80x94OH, a halogen, xe2x80x94CN, xe2x80x94OR6, xe2x80x94COOH, xe2x80x94CONR6R7, tetrazole, xe2x80x94CONHSO2R8, xe2x80x94COR6, xe2x80x94(CH2)nCH(OH)R6 and xe2x80x94(CH2)nCHR6R5;
R10 is independent of any other R group and is selected from the group consisting of xe2x80x94H, xe2x80x94OH, a halogen, xe2x80x94CN, xe2x80x94OR6, xe2x80x94COOH, xe2x80x94CONR6R7, tetrazole, xe2x80x94CONHSO2R8, xe2x80x94COR6, xe2x80x94(CH2)nCH(OH)R6 and xe2x80x94(CH2)nCHR6R5;
W is, independent each time used including within the same compound, selected from the group consisting of xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94CH2xe2x80x94, xe2x80x94CHxe2x95x90CHxe2x80x94, xe2x80x94Cxe2x89xa1Cxe2x80x94 and xe2x80x94N(R6)xe2x80x94;
X is independent of any other group and is, independently each time used including within the same compound, selected from the group consisting of xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94 and xe2x80x94N(R6)xe2x80x94;
Z is independent of any other group and is, independently each time used including within the same compound, selected from the group consisting of xe2x80x94CH2xe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94N(R6)xe2x80x94, xe2x80x94COxe2x80x94, xe2x80x94CON(R6)xe2x80x94 and xe2x80x94N(R6)COxe2x80x94;
m is, independently each time used including within the same compound, an integer from 0 to 4; and
n is independently of m and is, independently each time used including within the same compound, an integer from 0 to 4.
Drugs, 1998, 1(1): 49-50, discloses a limited series of cPLA2 inhibitors as shown below
U.S. Pat. No. 5,866,318 relates to methods for inhibiting cell death in mammalian cells, particularly in neuronal cells, by administering a suitable inhibitor of phospholipase A2 activity, typically an inhibitor of cPLA2.
Published Application WO 97/21676 discloses certain azetidinone compounds as phospholipase inhibitors in the treatment of atherosclerosis.
U.S. Pat. No. 5,453,443 discloses a series of biaryl ketones which are reported to inhibit PLA2 enzymes. These compounds have the generic formula 
wherein:
R1 is selected from
(a) hydrogen,
(b) xe2x80x94C1-6alkyl, and
(c) xe2x80x94C1-6alkyl-phenyl;
or wherein R1 and R5 are joined such that together with the carbon atoms to which they are attached there is formed a saturated or unsaturated carbon ring of 3, 4, 5, 6, 7 or 8 atoms;
R2 and R3 are each independently selected from
(a) hydrogen,
(b) xe2x80x94C1-6alkyl, and
(c) xe2x80x94C1-6alkyl-phenyl;
or wherein two R2 or two R3 are joined such that together with the carbon atoms to which they are attached there is formed a saturated or unsaturated carbon ring of 3, 4, 5, 6, 7 or 8 atoms;
R5 is as defined above or is selected from
(a) hydrogen,
(b) xe2x80x94C1-6alkyl,
(c) xe2x80x94C1-6alkyl-phenyl C1-6alkyl,
(d) xe2x80x94OH,
(e) xe2x80x94Oxe2x80x94C1-6alkyl, or
(f) xe2x80x94Oxe2x80x94C1-6alkyl-phenyl C1-6alkyl;
R6 is selected from
(a) hydrogen,
(b) xe2x80x94C1-6alkyl,
(c) xe2x80x94C1-6alkyl-phenyl, wherein the phenyl is optionally substituted with C1-2alkyl;
(d) xe2x80x94OH,
(e) xe2x80x94Oxe2x80x94C1-6alkyl, or
(f) xe2x80x94C1-6alkyl-phenyl, wherein the phenyl is optionally substituted with C1-2alkyl;
or wherein two R6 are joined to form Oxe2x95x90 or are joined together such that together with the carbon atom to which they are attached there is formed a saturated or unsaturated carbon ring of 3, 4, 5, 6, 7 or 8 atoms;
R8, R9 and R14 are each independently selected from
(a) H,
(b) xe2x80x94C1-6alkyl,
(c) halo,
(d) xe2x80x94CN,
(e) xe2x80x94OH,
(f) xe2x80x94OC1-6alkyl,
(g) xe2x80x94OC1-6alkyl-phenyl,
(h) xe2x80x94SR11,
(i) S(O)R11, or
S(O)2R11;
R10, R15, R16 and R17 are each independently selected from
(a) hydrogen,
(b) xe2x80x94C1-6 alkyl, and
(c) xe2x80x94C1-6 alkyl-phenyl;
R11 is selected from
(a) xe2x80x94C1-6 alkyl,
(b) xe2x80x94C2-6 alkenyl,
(c) xe2x80x94CF3,
(d) -phenyl(R12)2, or
(e) xe2x80x94C2-6 alkenyl-phenyl(R12)2;
R12 is
(a) hydrogen,
(b) xe2x80x94C1-6 alkyl,
(c) Cl, F, I or Br;
R13 is perfluoro C1-6alkyl;
A and B are each independently
(a) covalent bond,
(b) O,
(c) S,
(d) S(O), or
(e) S(O)2;
Q is selected from
(a) xe2x80x94CH(OH)R13,
(b) xe2x80x94COR13,
(c) xe2x80x94COR16, or
(d) xe2x80x94C1-4alkylCOCOOR17;
X1 is selected from
(a) xe2x80x94Oxe2x80x94,
(b) xe2x80x94Sxe2x80x94,
(c) xe2x80x94S(O)xe2x80x94,
(d) xe2x80x94S(O)2xe2x80x94;
Z is
(a) H, or
(b) -phenyl-(R14)3;
m is 0, 1, 2, 3 or 4;
n is 2, 3, 4, 5, 6 or 7; and
r and s are each independently 0, 1, 2, 3, 4, 5, 6, 7 or 8.
Published Application WO 99/15129 discloses selective cPLA2 inhibitors having the formula 
wherein
W is CHxe2x95x90CH, CHxe2x95x90N, O or S;
R1 is (C1-C6)alkyl, (C2-C6)alkenyl, (C2-C6)alkynyl, (C1-C6)alkoxy, (C1-C6)alkylthio, halo, hydroxy, cyano, 
xe2x80x83in which R2 and R3 are each independently hydrogen or (C1-C6)alkyl, xe2x80x94COOxe2x80x94(C1-C6)alkyl, CF3, (C1-C6)alkylphenyl, phenyl or phenyl substituted by one or more, preferably 1-3, of (C1-C6)alkyl, xe2x80x94COOxe2x80x94(C1-C6)alkyl, 
xe2x80x83in which R2 and R3 are as defined above, halo, hydroxy, xe2x80x94Oxe2x80x94(C1-C6)alkyl, xe2x80x94Sxe2x80x94(C1-C6)alkyl or (C2-C6)alkenyl;
p is 0, 1 or 2;
A is Vxe2x80x94(Rc)nxe2x80x94;
Rc is a straight or branched chain alkyl group;
n is 0 or an integer of from 1 to 6;
Ra and Rb when taken together form an oxo (xe2x95x90O) group, or Ra and Rb are each independently hydrogen or OH;
V is O, xe2x80x94Sxe2x80x94, xe2x80x94SOxe2x80x94, xe2x80x94SO2, xe2x80x94CONH or NHCO when n is an integer of from 1 to 6 or V is (C2-C6) alkenyl or a bond when n is 0 or an integer of from 1 to 6;
D is xe2x80x94(CH2)m or a bond linking the 
xe2x80x83ring to Y;
m is an integer of from 1 to 6;
Y is xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94SOxe2x80x94, xe2x80x94SO2; 
xe2x80x83or a bond;
R4 is as defined below for R7;
Z is 
xe2x80x83in which B is: 
xe2x80x83xe2x80x94SO2xe2x80x94 or a bond;
X is S or O;
q is an integer from 1 to 6;
R9 is hydrogen or (C1-C6)alkyl;
R10 is hydrogen, CN, NO2, OH, xe2x80x94Oxe2x80x94(C1-C6)alkyl, (C1-C6) alkyl, phenyl or (C1-C6)alkylphenyl;
R5 and R6 are each independently hydrogen or (C1-C18) alkyl;
R7 and R8 are each independently
(a) hydrogen;
(b) (C1-C18)alkyl;
(c) (C1-C18)alkyl substituted by one or more of
(1) phenyl;
(2) phenyl substituted by 1-5 fluoro, 1-3 (for each of the following phenyl substituents) halo (other than fluoro), 1-3 (C1-C6)alkoxy, 1-3(C1-C6)alkyl, nitro, cyano, hydroxy, trifluoromethyl, (C1-C6)alkylthio, amino, 1-3 (C1-C6) alkylamino, di(C1-C6)alkylamino, xe2x80x94CO2H, xe2x80x94COOxe2x80x94(C1-C6)alkyl, xe2x80x94SO3H, xe2x80x94SO2NHR15 in which R15 is hydrogen or (C1-C6)alkyl, or 
xe2x80x83in which R2 and R3 are as defined above;
(3) heterocyclic selected from oxadiazolyl, isoxazolyl, oxazolyl, furyl and thiazolyl;
(4) heterocyclic substituted by one or more of, preferably 1-3, phenyl, phenyl substituted by 1-3 (for each of the following) halo, (C1-C6)alkoxy, (C1-C6)alkyl, nitro, cyano, hydroxy, trifluoromethyl, (C1-C6)alkylthio, amino, (C1-C6)alkylamino, di(C1-C6)alkylamino, CO2H, xe2x80x94COOxe2x80x94(C1-C6)alkyl, xe2x80x94SO3H, SO2NHR15 in which R15 is hydrogen or (C1-C6)alkyl, or 
xe2x80x83in which R2 and R3are as defined above, (C1-C6)alkyl or (C1-C6)alkyl substituted by one or more, preferably 1-3, phenyl or heterocyclic groups, said phenyl or heterocyclic group being unsubstituted or substituted by 1-3 (for each of the following) halo, 1-3 (C1-C6)alkoxy, 1-3 (C1-C6)alkyl, nitro, cyano, hydroxy, trifluoromethyl, (C1-C6)alkylthio, amino, 1-3 (C1-C6)alkylamino, di(C1-C6)alkylamino, COOH, xe2x80x94COOxe2x80x94(C1-C6)alkyl, xe2x80x94SO3H, xe2x80x94SO2NHR15 in which R15 is hydrogen or (C1-C6)alkyl, or 
xe2x80x83in which R2 and R3 are each independently hydrogen or (C1-C6)alkyl, the heterocyclic radical being selected from imidazolyl, oxadiazolyl, isoxazolyl, pyrrolyl, pyrazolyl, oxazolyl, furyl, thianyl or thiazolyl;
(5) carboxy or xe2x80x94COOxe2x80x94(C1-C6)alkyl;
(6) hydroxy, halo, xe2x80x94Oxe2x80x94(C1-C6) alkyl or xe2x80x94Sxe2x80x94(C1-C6)alkyl, with the proviso that the OH, ethers or thioethers cannot be on the carbon bearing the heteroatoms;
(7) cyano;
(8) halo, trifluoromethyl or trifluoroacetyl;
(9) CH2 Lxe2x80x94R16 in which L is 
xe2x80x83xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94SOxe2x80x94, xe2x80x94SO2xe2x80x94, 
xe2x80x83or xe2x80x94Oxe2x80x94SiR16R18R19 or a bond in which R16 and R17 are each independently (C1-C18)alkyl or (C2-C18)alkenyl or (C1-C18)alkyl or (C2-C18)alkenyl substituted by one or more, preferably 1-3, phenyl or heterocyclic radicals, said phenyl or heterocyclic radicals being unsubstituted or substituted by 1-5 fluoro, 1-3 halo (other than fluoro), 1-3 (C1-C6)alkoxy, 1-3(C1-C6)alkyl, nitro, cyano, hydroxy, 1-3 trifluoromethyl, 1-3 (C1-C6)alkylthio, amino, 1-3(C1-C6)alkylamino, 1-3 di(C1-C6)alkylamino, CO2H, 1-3 xe2x80x94COO(C1-C6)alkyl, 
xe2x80x83or xe2x80x94SO2NHR9 in which R9 is hydrogen or (C1-C6)alkyl and R2 and R3 are as defined above; 
xe2x80x83in which B is 
xe2x80x83xe2x80x94SO2xe2x80x94, xe2x80x94PO(OR9)2 or a bond; providing that when B1 is xe2x80x94PO(OR9)2; then R7 becomes R9, and when B1 is 
xe2x80x83or xe2x80x94SO2xe2x80x94, then R7 cannot be hydrogen;
X, q, R5, R6, R7, R8, R9 and R10 are as defined in (a); 
xe2x80x83in which q, R5 and R6 are as defined above;
R18, R19 and R11 are as defined above for R7 and R8 except that they may not be hydrogen, or R18 and R19 taken together with the nitrogen to which they are attached represent a 4, 5- or 6-membered heterocyclic ring and Y, R7 and R11 are as defined above, or R18, R19 and R11 taken together with the nitrogen to which they are attached represent pyridinium, said pyridinium group being unsubstituted or substituted by (C1-C12)alkyl, (C1-C12)alkoxy, amino, (C1-C12)alkylamino, di(C1-C12)alkylamino, 
xe2x80x94Sxe2x80x94(C1-C12)alkyl, 
xe2x80x83in which R2 and R3 are as defined above, phenyl or phenyl (C1-C10)alkyl; 
xe2x80x83in which R13 is (C1-C18)alkyl or (C1-C18)alkyl substituted by carboxy, 
xe2x80x83in which R2 and R3 are as defined above, hydroxy, xe2x80x94Oxe2x80x94(C1-C6) alkyl, xe2x80x94Oxe2x80x94(C1-C6) alkyl or xe2x80x94Sxe2x80x94(C1-C6) alkyl substituted by 1 or 2 phenyl or substituted phenyl groups, the substituents for the substituted phenyl groups being 1-5 fluoro or 1-3 (for each of the following phenyl substituents) halo (other than fluoro), (C1-C6)alkoxy, (C1-C6)alkyl, nitro, cyano, hydroxy, trifluoromethyl, (C1-C6)alkylthio, amino, (C1-C6) alkylamino, di(C1-C6) alkylamino, CO2H, COOxe2x80x94(C1-C6) alkyl, SO3H, SO2NHR15 in which R15 is hydrogen or (C1-C6) alkyl or 
xe2x80x83in which R2 and R3 are as defined above;
r is 0 or an integer of from 1 to 3;
R7 is as defined above;
M is xe2x80x94(CH2xe2x80x94)mT where T is 
xe2x80x83in which R2 is as defined above, xe2x80x94SO2xe2x80x94 or a bond when MR7 is on nitrogen and providing that when T is 
xe2x80x83or xe2x80x94SOxe2x80x94 or xe2x80x94SO2xe2x80x94, then R7 cannot be hydrogen, and T is 
xe2x80x83xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94SOxe2x80x94, xe2x80x94SO2xe2x80x94, 
xe2x80x83or a bond when MR7 is on a carbon atom of the heterocyclic ring;
R14 is hydrogen or (C1-C6)alkyl;
m is 0 or an integer of 1-6; 
xe2x80x83wherein Q is xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94SOxe2x80x94 or xe2x80x94SO2xe2x80x94, and q, R5, R6 and R7 are as defined above, providing that when Q is xe2x80x94SOxe2x80x94 or xe2x80x94SO2xe2x80x94, R7 cannot be hydrogen;
(f) R7 wherein R7 is defined above, providing that when Y is xe2x80x94SOxe2x80x94 or xe2x80x94SO2xe2x80x94, R7 cannot be hydrogen; and
R18 and R19 are phenyl or phenyl substituted by 1-3 halo, (C1-C6)alkoxy, (C1-C6)alkyl, nitro, cyano, hydroxy, trifluoromethyl, (C1-C6)alkylthio, amino, (C1-C6)alkylamino, di(C1-C6)alkylamino, CO2H, xe2x80x94COOxe2x80x94(C1-C6)alkyl, xe2x80x94SO3H, SO2NHR15 in which R15 is hydrogen or (C1-C6)alkyl, or 
xe2x80x83in which R2 and R3 are as defined above; or pharmaceutically acceptable salts, solvates or prodrugs thereof.
R18 and R19 are phenyl or phenyl substituted by 1-3 halo, (C1-C6)alkoxy, (C1-C6) alkyl, nitro, cyano, hydroxy, trifluoromethyl, (C1-C6) alkylthio, amino, (C1-C6) alkylamino, di(C1-C6)alkylamino, CO2H, xe2x80x94COOxe2x80x94(C1-C6)alkyl, xe2x80x94SO3H, SO2NHR15 in which R15 is hydrogen or (C1-C6)alkyl, or 
xe2x80x83in which R2 and R3 are as defined above; or pharmaceutically acceptable salts, solvates or prodrugs thereof.
There is nothing in any of the foregoing references, or in the general prior art, to suggest the novel alpha beta substituted trifluoromethyl-ketones of the present invention as cytosolic phospholipase A2 inhibitors.
An object of the present invention is to provide novel alpha and/or beta substituted trifluoromethylketone compounds which inhibit cytosolic phospholipase A2 enzymes that are pro-inflammatory mediators. Some of the derivatives exhibit increased stability and aqueous solubility.
This invention relates to novel cytosolic phospholipase inhibitors represented by formula I, or a pharmaceutically acceptable salt thereof 
wherein
Ra and Rb when taken together form an oxo (xe2x95x90O) group, or Ra and Rb are each independently hydrogen or OH;
X is H, CF3, halogen, NR5R6, NH(CO)NR5R6, C(O)NR5R6, OH, OR7, SH, S(O)nR7, C(O)OR8, NH(CO)OR10 C1-C7 alkyl, C2-C7 alkenyl, C2-C7 alkynyl or C3-C7 cycloalkyl, said alkyl, alkenyl, alkynyl or cycloalkyl group being optionally substituted by COOR8, CN, C(O)NR5R6, PO3R8, SO3R8, heterocyclic, OH, OR7, SH, S(O)nR7, NR5R6, NH(CO)NR5R6, NH(CO)OR10, OC(O)OR10, aryl or heteroaryl, said aryl or heteroaryl being optionally substituted by one or two groups independently selected from COOR8, SO3R8, OCOR8, PO3R8 or heterocyclic;
R1 and R2 are each independently H, OH, OR7, SH, S(O)nR7, substituted C1-C7 alkyl, C2-C7 alkenyl, C2-C7 alkynyl or C3-C7 cycloalkyl, said alkyl, alkenyl, alkynyl or cycloalkyl group being substituted by COOR8, CN, C(O)NR5R6, PO3R8, SO3R8, heterocyclic, OH, OR7, SH, S(O)nR7, NR5R6, NH(CO)NR5R6, NH(CO)OR10, OC(O)OR10, aryl or heteroaryl, said aryl or heteroaryl group being optionally substituted by one or two groups independently selected from COOR8, SO3R8, PO3R8 or heterocyclic;
R3 and R4 are each independently H, methylene, OH, OR7, SH, S(O)nR7, NHCOR7, COOR8, C(O)NR5R6, substituted C1-C7 alkyl, C2-C7 alkenyl, C2-C7 alkynyl or C3-C7 cycloalkyl, said alkyl, alkenyl, alkynyl or cycloalkyl group being substituted by COOR8, CN, C(O)NR5R6, PO3R8, SO3R8, heterocyclic, OH, OR7, SH, S(O)nR7, NR5R6, NH(CO)NR5R6, NH(CO)OR10, OC(O)OR10, aryl or heteroaryl, said aryl or heteroaryl group being optionally substituted by one or two groups independently selected from COOR8, SO3R8, PO3R8 or heterocyclic;
R5 and R6 are each independently H, C1-C7 alkyl, C2-C7 alkenyl, C2-C7 alkynyl, C3-C7 cycloalkyl, heterocyclic, aryl or heteroaryl, said alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl or heteroaryl group being optionally substituted with COOR8, CN, OR8, NR8R9, SO3R8, PO3R8, halogen, aryl or heteroaryl, said aryl or heteroaryl substituent being optionally substituted with one or two groups independently selected from COOR8, SO3R8, PO3R8 or heterocyclic;
R7 is C1-C7 alkyl or C3-C7 cycloalkyl, said alkyl or cycloalkyl group being optionally substituted by COOR8, CN, C(O)NR5R6, PO3R8, SO3R8, heterocyclic, OR5, SR5, S(O)nR10, NR5R6, NH(CO)NR5R6, NH(CO)OR10, C(O)2OR10, aryl or heteroaryl, said aryl or heteroaryl group being optionally substituted with one or two groups independently selected from COOR8, SO3R8, PO3R8 or heterocyclic;
R8 and R9 are each independently H, C1-C7 alkyl or C3-C7 cycloalkyl;
R10 is the same as R5 and R6 but is not H;
Z is OR11, S(O)nR11, NR11R12 or CHR11R12;
R11 and R12 are each independently hydrogen, C1-C7 alkyl, C2-C7 alkenyl, C2-C7 alkynyl or C3-C7 cycloalkyl, said alkyl, alkenyl, alkynyl or cycloalkyl group being optionally substituted with NR13R14, SR13, S(O)R18, SO2R18 or OR13, with the proviso that both R11 and R12 may not both be hydrogen;
R13 and R14 are each independently H, SiR15R16R17, C1-C7 alkyl, C2-C7 alkenyl, C2-C7 alkynyl or C3-C7 cycloalkyl or aryl, said alkyl, alkenyl, alkynyl, cycloalkyl or aryl group being optionally substituted with 1-3 COOR8, OR8, SiR15R16R17, OR15, aryl, biaryl or heteroaryl, said aryl, biaryl or heteroaryl group being optionally substituted with 1-3 halogen, CF3, OR8, COOR8, NO2 or CN, or R13 and R14 when taken together with the nitrogen to which they are attached form a 5-7 membered heterocyclic ring with one or more O, N or S heteroatoms, said ring being optionally substituted with COOR8 or C1-C5 alkyl optionally substituted with OR8, COOR8 or C(O)NR5R6;
R15, R16 and R17 are each independently aryl, benzyl, benzhydryl, biaryl, heteroaryl, aryl(C1-C6)alkyl or heteroaryl(C1-C6)alkyl, said aryl group being optionally substituted with halogen, CF3, OR8, COOR8, NO2, CN or C1-C7 alkyl;
R18 is the same as R13 and R14 but is not H;
n is 0, 1 or 2; or a pharmaceutically acceptable salt thereof, with the proviso that at least one of R1, R2, R3 and R4 is other than hydrogen.
Another aspect of this invention involves methods for inhibiting cytosolic PLA2 in a mammal in need thereof which comprises administering to said mammal a therapeutically effective amount of a compound of formula I and methods for using the compounds of formula I to treat various diseases characterized by inappropriate activation of the cytosolic PLA2 enzymes such as asthma, allergic rhinitis, cerebral ischemia, Alzheimer""s Disease, rheumatoid arthritis, acute pancreatitis, inflammatory bowel disease, psoriasis, gout, neutrophil and platelet activation, chronic skin inflammation, shock, trauma-induced inflammation such as spinal cord injury, damage to the skin resulting from UV light or burns and macrophage activation. In further aspects, the present invention provides pharmaceutical compositions comprising a therapeutically effective amount of a compound of formula I and a pharmaceutically acceptable carrier and processes for preparing the compounds of formula I.
The object of this invention was to discover a selective cPLA2 inhibitor which is active, both topically and orally, in treating inflammatory disease of the skin and other tissues as well as other chronic and acute conditions which have been linked to inappropriate activation of the cPLA2 enzymes. Preferably such compound would also be devoid of undesirable lipid-perturbing activities associated with skin irritation.
The above-mentioned objectives have been met by the compounds of formula I described above.
Definitions
In the present application the numbers in the subscript after the symbol xe2x80x9cCxe2x80x9d define the number of carbon atoms a particular group can contain. For example, xe2x80x9cC1-C7 alkylxe2x80x9d refers to straight and branched chain alkyl groups with 1 to 7 carbon atoms. Similarly, xe2x80x9cC2-C7 alkenyl refers to an unsaturated hydrocarbon group containing from 2 to 7 carbon atoms and at least one carbon-carbon double bond. The term xe2x80x9cC2-C7alkynylxe2x80x9d refers to an unsaturated hydrocarbon group containing from 2 to 7 carbon atoms and at lease one triple bond.
The term xe2x80x9chalogenxe2x80x9d or xe2x80x9chaloxe2x80x9d as used herein refers to fluorine, chlorine, bromine or iodine.
xe2x80x9cArylxe2x80x9d as used herein refers to a C6 monocyclic aromatic ring system or a C9 or C10 bicyclic carbocyclic ring system having one or two aromatic rings such as phenyl or naphthyl. It may also refer to a C14 tricyclic carbocyclic ring system having two or three aromatic rings such as anthracenyl or phenanthrenyl. Unless otherwise indicated, xe2x80x9csubstituted arylxe2x80x9d refers to aryl groups substituted with one or more (preferably from 1 to 3) substituents independently selected from (C1-C6)alkyl, halo(C1-C6)alkyl, (C1-C6)alkoxy, (C1-C6)alkoxy-carbonyl, (C1-C6)alkanoyl, hydroxy, halo, mercapto, nitro, amino, cyano, (C1-C6)alkylamino, di(C1-C6)alkylamino, carboxy, aryl, aryl (C1-C6)alkyl, aryl (C1-C6)alkoxy, heterocyclic, heterocyclic (C1-C6)alkyl and the like. The term xe2x80x9cbiarylxe2x80x9d refers to two C6 monocyclic aromatic ring systems or two C9 or C10 bicyclic carbocyclic ring systems linked together such as o-, m- and p-biphenyl or o-, m- and p-binaphthyl. The term xe2x80x9cheteroarylxe2x80x9d refers to a 5- or 6-membered aromatic ring system or a 9- or 10-membered bicyclic aromatic ring system containing one, two or three heteroatoms selected from N, O and S. The term xe2x80x9cbenzhydrylxe2x80x9d refers to a carbon atom bearing two aryl, bis-aryl or heteroaryl groups.
The term xe2x80x9cheterocyclicxe2x80x9d as used herein refers to a 4-, 5- or 6-membered ring containing one, two or three heteroatoms selected from N, O and S. The 5-membered ring has 0-2 double bonds and the 6-membered ring has 0-3 double bonds. The nitrogen heteroatoms can be optionally quaternized or N-oxidized. The sulfur heteroatoms can be optionally S-oxidized. The term xe2x80x9cheterocyclicxe2x80x9d also includes bicyclic groups in which any of the above heterocyclic rings is fused to a benzene ring or a cyclohexane ring or another heterocyclic ring. Heterocyclics include: pyrrolyl, pyrrolinyl, pyrrolidinyl, pyrazolyl, pyrazolinyl, pyrazolidinyl, imidazolyl, imidazolidinyl, pyridyl, piperidyl, pyrazinyl, piperazinyl, pyrimidinyl, pyridazinyl, oxazolyl, oxazolinyl, oxazolidinyl, isoxazolyl, isoxazolinyl, isoxazolidinyl, morpholinyl, thiazolyl, thiazolidinyl, isothiazolyl, isothiazolidinyl, indolyl, quinolinyl, benzimidazolyl, benzothiazolyl, benzoxazolyl, benzofuranyl, furyl, dihydrofuranyl, tetrahydrofuranyl, pyranyl, dihydropyranyl, dioxolanyl, thienyl, benzothienyl and diaxanyl.
In a preferred embodiment, the Z substituent in the compounds of formula I is in the para-position.
In another preferred embodiment, the R1 and R2 substituents of a compound of formula I are both hydrogen.
In another preferred embodiment, the R3 and R4 substituents of a compound of formula I are both hydrogen.
In another preferred compound, substituent Z in the compounds of formula I is Yxe2x80x94Z1 in which
Y is xe2x80x94Oxe2x80x94, xe2x80x94S(O)nxe2x80x94, 
n is 0, 1 or 2;
Rc is H, xe2x80x94COCF3, xe2x80x94COC6H5, xe2x80x94COO(C1-C6)alkyl, 
xe2x80x83in which R19 and R20 are each independently H or (C1-C6)alkyl, (C1-C18)alkyl or (C1-C18)alkyl substituted by one or more of phenyl or phenyl substituted by 1-5 fluoro, 1-3 halo (other than fluoro), 1-3 (C1-C6)alkoxy, 1-3 (C1-C6)alkyl, 1-3 nitro, 1-3 cyano, 1-3 hydroxy, 1-3 trifluoromethyl, 1-3 (C1-C6)alkylthio, 1-3 amino, 1-3 (C1-C6)alkylamino, 1-3 di(C1-C6)alkylamino, 1-3 carboxyl, 1-3 xe2x80x94COO(C1-C6)alkyl, 1-3 xe2x80x94SO3H, 1-3 xe2x80x94SO2NHR21 in which R21 is hydrogen or (C1-C6)alkyl, or 
xe2x80x83in which R19 and R20 are as defined above; and
Z1 is 
xe2x80x83in which n1 is 0, 1 or 2 and R22 and R23 are phenyl or phenyl substituted by 1-5 fluoro, 1-3 halo (other than fluoro), 1-3 (C1-C6)alkoxy, 1-3 (C1-C6)alkyl, 1-3 nitro, 1-3 cyano, 1-3 hydroxy, 1-3 trifluoromethyl, 1-3 (C1-C6)alkylthio, 1-3 amino, 1-3 (C1-C6)alkylamino, 1-3 di(C1-C6)alkylamino, 1-3 carboxy, 1-3 xe2x80x94COO(C1-C6)alkyl, 1-3 xe2x80x94SO3H, 1-3 xe2x80x94SO2NHR21 in which R21 is hydrogen or (C1-C6)alkyl, or 
xe2x80x83in which R19 and R20 are as defined above; 
xe2x80x83in which n1 is 0, 1 or 2 and R22 and R23 are as defined above;
(c) 
xe2x80x83in which R22 and R23 are as defined above;
(d) 
xe2x80x83in which R22 and R23 are as defined above;
(e) 
xe2x80x83in which R22 and R23 are as defined above; or
(f) 
xe2x80x83in which R22 and R23 are as defined above.
Within this preferred subground, more preferred compounds are those wherein R1 and R2 are both hydrogen, R3 is hydrogen, R4 is xe2x80x94OH, xe2x80x94OCH3, xe2x80x94O-i-propyl, xe2x80x94CH2OH, xe2x80x94CH2OCH2OCH3, xe2x80x94COOCH3, xe2x80x94(CH2)vCOO-t-butyl, xe2x80x94(CH2)vCOOC2H5, xe2x80x94(CH2)vCOOH, 
and v is 0 or an integer of from 1-6.
Other preferred compounds within this subgroup are those wherein R1, R3 and R4 are hydrogen, R2 is xe2x80x94S(CH2)vCOO-t-butyl, xe2x80x94Sxe2x80x94(CH2)vCO2H, xe2x80x94(CH2)vCOO-t-butyl, xe2x80x94(CH2)vCO2H, 
and v is 0 or an integer of from 1-6.
A most preferred embodiment embraces compounds of formula I wherein X is H.
Some of the compounds described herein contain one or more asymmetric centers and may thus give rise to diastereomers and optical isomers. The present invention is meant to include such possible diastereomers as well as their racemic and resolved, enantiomerically pure forms, and pharmaceutically acceptable salts thereof.
As mentioned above the invention also includes pharmaceutically acceptable salts of the compounds of formula I. A compound of the invention can possess a sufficiently acidic, a sufficiently basic, or both functional groups. Accordingly, a compound may react with any of a number of inorganic bases, and organic and inorganic acids, to form a pharmaceutically acceptable salt.
The term xe2x80x9cpharmaceutically acceptable saltxe2x80x9d as used herein refers to salts of the compounds of formula I which are substantially non-toxic to living organisms. Typical pharmaceutically acceptable salts include those salts prepared by reaction of the compounds of the present invention with a pharmaceutically acceptable mineral or organic acid or an inorganic base. Such salts are known as acid addition and base addition salts.
Acids commonly employed to form acid addition salts are inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, and the like, and organic acids such as p-toluenesulfonic, methanesulfonic acid, oxalic acid, p-bromophenylsulfonic acid, carbonic acid, succinic acid, citric acid, benzoic acid, acetic acid, and the like. Examples of such pharmaceutically acceptable salts are the sulfate, pyrosulfate, bisulfate, sulfite, bisulfite, phosphate, monohydrogen phosphate, dihydrogen phosphate, metaphosphate, pyrophosphate, chloride, bromide, iodide, acetate, propionate, decanoate, caprylate, acrylate, formate, isobutyrate, caproate, heptanoate, propionate, oxalate, malonate, succinate, suberate, sebacate, fumarate, maleate, butyne-1,4-dioate, hexyne-1,6-dioate, benzoate, chlorobenzoate, methylbenzoate, dinitrobenzoate, hydroxybenzoate, methoxybenzoate, phthalate, sulfonate, xylene-sulfonate, phenylacetate, phenylpropionate, phenylbutyrate, citrate, lactate, xcex3-hydroxybutyrate, glycolate, tartrate, methanesulfonate, propanesulfonate, naphthalene-1-sulfonate, napthalene-2-sulfonate, mandelate and the like. Preferred pharmaceutically acceptable acid addition salts are those formed with mineral acids such as hydrochloric acid and hydrobromic acid, and those formed with organic acids such as maleic acid and methanesulfonic acid.
Base addition salts include those derived from inorganic bases, such as ammonium or alkali or alkaline earth metal hydroxides, carbonates, bicarbonates, and the like. Such bases useful in preparing the salts of this invention thus include sodium hydroxide, potassium hydroxide, ammonium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, potassium bicarbonate, calcium hydroxide, calcium carbonate, and the like. Suitable organic bases include trialkylamines such as triethylamine, procaine, dibenzylamine, N-benzyl-xcex2-phenethylamine, 1-ephenamine, N,Nxe2x80x2-dibenzylethylene-diamine, dehydroabietylamine, N-ethylpiperidine, benzylamine, dicyclohexylamine, or the like pharmaceutically acceptable amines. The potassium and sodium salt forms are particularly preferred.
It should be recognized that the particular counterion forming a part of any salt of this invention is usually not of a critical nature, so long as the salt as a whole is pharmacologically acceptable and as long as the counterion does not contribute undesired qualities to the salt as a whole.
The present invention also includes solvated forms of the compounds of formula I, particularly hydrates, in which the trifluoromethyl ketone group exists as a mixture of ketonic I and hydrated forms II and are each independently interconvertible and pharmacologically active. 
As used herein and in the reaction schemes the term xe2x80x9creductionxe2x80x9d is intended to include well-known reduction procedures of ester groups by the use of aluminum or boron hydrides such as lithium aluminum hydride, aluminum hydride, diisobutylaluminum hydride, sodium borohydride, sodium cyanoborohydride and the like in an inert organic solvent such as tetrahydrofuran, ethyl ether, ethanol, dichloromethane and the like. The term xe2x80x9creductionxe2x80x9d is also intended to include the various methods of reducing unsaturated bonds. Well-known hydrogenolysis procedures using hydrogen with a catalyst such as palladium or platinum on charcoal, palladium or platinum hydroxide on charcoal, rhodium on charcoal in a solvent such as ethanol or ethyl acetate may be used if appropriate. Other methods including the use of hydrazine or triethylsilane and the Wilkinson""s catalyst or a metal in methanol such as magnesium for example may also be useful.
As used herein and in the reaction schemes, the term xe2x80x9chydrolysisxe2x80x9d is intended to include conventional hydrolysis procedures of esters well-known to those skilled in the art. For example, methyl or ethyl esters may be removed by the use of aqueous solutions of sodium or potassium alkoxides in tetrahydrofuran or ethanol. The hydrolysis of tert-butyl esters are carried out under acidic conditions such as 90% trifluoroacetic acid or 6N hydrochloric acid in solvents such as tetrahydrofuran or dichloromethane. Allyl esters may be removed by the use of Pd(0) catalyst such as sodium acetate, potassium or sodium 2-ethylhexanoate, pyrolidine or morpholine and the like in an organic solvent such as acetonitrile, tetrahydrofuran, dichloromethane and the like. Finally, silyl esters such as trimethylsilylethyl esters may be cleaved by the use of tetrabutylammonium fluoride in tetrahydrofuran.
As used herein and in the reaction schemes, the term xe2x80x9cenol triflate or enol formationxe2x80x9d is intended to include conventional and well-known enolate formation procedures and subsequent trapping of this enolate by the well-known triflating or silylating agents. Thus the ketones are treated with an organic base such as 2,6-di-tert-butyl-4-methyl-pyridine, sodium hydride, potassium hydride, lithium diisopropylamide or lithium bis(trimethylsilyl)amide in an inert organic solvent such as tetrahydrofuran, dimethylformamide or dichloromethane and the like. The resulting enolates are then reacted with triflic anhydride or 2-[N,N-bis(trifluoromethylsulfonyl)amino]pyridine and the like or an alkylsilyl halides or triflates.
As used herein and in the reaction schemes, the term xe2x80x9ccross-couplingxe2x80x9d is intended to include all the cross-coupling methods well-known by those skilled in the art that involve the reaction of a vinyl or aromatic triflate, bromide or iodide with a tin, zinc, magnesium or boronic derivative catalyzed by a palladium(0) or palladium(II) catalyst such as tetrakis(triphenyl-phosphine)palladium(0), bis(triphenylphosphine)palladium(II) chloride, palladium(II) acetate, tris(dibenzylidene-acetone)dipalladium(0), bis(diphenylphosphineferrocene)palladium(II) chloride and the like or a nickel(0) or nickel(II) catalyst such as tetrakis(triphenylphosphine)nickel(0), bis(triphenylphosphine)nickel(II) chloride and the like. Very often, as known by those skilled in the art, copper iodide, lithium chloride, zinc chloride or triphenylarsine, tris(2-furyl)phosphine or tris(2,4,6-trimethoxyphenyl)phosphine must be added. When a boronic acid derivative is used, the reaction proceeds only in the presence of an inorganic base such as potassium phosphate or carbonate or sodium carbonate. These reactions are performed in an inert organic solvent such as dioxane, N-methylpyrrolidone, dimethylformamide, dimethoxyethane, tetrahydrofuran, toluene, benzene and the like.
As used herein and in the reaction schemes the term xe2x80x9calkylationxe2x80x9d is intended to include conventional and well-known alkylation procedures. Thus, the desired alcohol or ketone groups which are to be alkylated are treated in the presence of an organic or inorganic base such as sodium hydride, potassium hydride, lithium diisopropylamine or lithium bis(trimethylsilyl)amide in an inert organic solvent such as tetrahydrofuran, dimethylformamide, hexamethylphosphoramide, dimethylsulfoxide, N-methylpyrolidinone and the like. Then an alkylating agent such as an alkyl, allyl or benzyl halide, mesylate or tosylate is added to this generated enolate, alcoholate, phenolate or thiophenolate.
As used herein and in the reaction schemes, the term xe2x80x9cMichael additionxe2x80x9d is intended to include all conventional methods of conjugate addition of organometallic compounds or anions formed from malonates, cyanoacetates, acetoacetates, xcex2-ketoesters, esters, ketones, alkehydes, nitriles, nitro compounds, sulfones and the like to an xcex1, xcex2-unsaturated ketone. The organometallic compounds include lithium dialkylcopper, organoaluminum, trialkylzinc lithium, arylpalladium, arylmercury, borane reagents and the like. The inert organic solvents used may be tetrahydrofuran, dioxane, dimethylformamide, dichloromethane, benzene and the like.
As used herein and in the reaction schemes, the term xe2x80x9cepoxidationxe2x80x9d is intended to include the well-known methods of epoxide formation by reaction of an olefin with a peracid, preferably m-chloroperbenzoic acid or peracetic acid in a solvent such as dichloromethane and the like.
As used herein and in the reaction schemes, the term xe2x80x9chydroxylationxe2x80x9d is intended to include all the synthetic methodologies introducing and hydroxyl group at position a to a carbonyl functionality. Hence the enol or enolate of the carbonyl functionality is formed by reaction with a base such as sodium hydride, potassium hydride, lithium diisopropylamine or lithium bis(trimethylsilyl)amide in an inert organic solvent such as tetrahydrofuran, dimethylformamide, hexamethylphosphoramide, dimethylsulfoxide, N-methylpyrolidinone and the like. Subsequent reaction with the various oxidizing agents such as trans-2-phenylsulfonyl-3-phenyloxaziridine or trimethylsilylhydroperoxide and the like is then performed.
As used herein and in the reaction schemes the term xe2x80x9cacylationxe2x80x9d is intended to include conventional and well-known acylation procedures for the preparation of amides such as the use of leaving groups and activating groups on the acyl portion of the fatty acid. For example, the use of acid chlorides and carbodiimide as activating groups in organic solvent such as tetrahydrofuran, dichloromethane or mixture of aqueous-organic solvents in the presence of a base such as triethylamine, pyridine, dimethylaminopyridine and 50% sodium acetate.
Biological Activity
The assay determining the activity of cPLA2 inhibitors is the following:
3H-arachidonate-labeled U937 membranes were prepared from U937 cells grown in RPMI 1640 medium containing L-glutamine supplemented with 10% fetal calf serum and 50 xcexcg/ml gentamycin in a 5% CO2 incubator at 37xc2x0 C. Sixteen hours prior to harvesting the cells, 3H-arachidonate (100 Ci/mmol) was added to the cell culture (1xc3x97106 cells/ml, 0.5 xcexcCi/ml). After washing the cells with HBSS (Hank""s Balanced Salts) containing 1 mg/ml HSA (Human Serum Albumin), the cells were lysed by nitrogen cavitation and the homogenate was centrifuged at 2,000xc3x97g for 10 minutes. The supernatant was further centrifuged at 50,000xc3x97g for 30 minutes after which the pellet was resuspended in water and autoclaved at 120xc2x0 C. for 15 minutes to inactivate any residual phospholipase A2 activity. This suspension was then recentrifuged at 50,000xc3x97g for 30 minutes and the pellet resuspended in distilled water.
Assays of cPLA2 activity using these 3H-arachidonate-labeled U937 membranes as substrate typically employ human recombinant cPLA2 [see Burke et al., Biochemistry, 1995, 34: 15165-15174] and membrane substrate (22 xcexcM phospholipid) in 20 mM HEPES [N-(2-hydroxyethyl)piperazine-N1-(2-ethanesulfonic acid)] buffer, pH 8, containing 6 mM CaCl2, 0.9 mg/ml albumin and 4 M glycerol. Enzyme assays are allowed to proceed for 3 hours at 37xc2x0 C. before removing the non-hydrolyzed membranes. The hydrolyzed, radiolabeled fatty acid is then measured by liquid scintillation counting of the aqueous phase.
The effects of inhibitor are calculated as percent inhibition of 3H-arachidonate formation, after correcting for nonenzymatic hydrolysis, as compared to a control lacking inhibitor according to the following formula:
percent inhibition=((Control DPMxe2x88x92Inhibitor DPM)/Control DPM)xc3x97100%
Various concentrations of an inhibitor were tested, and the percent inhibition at each concentration was plotted as log concentration (abscissa) versus percent inhibition (ordinate) to determine the IC50 values.
In this assay the compounds of Examples 1 shown below exhibited cPLA2 IC50 values in the range of from about 1 to 50 xcexcm.
Since the compounds of the present invention are selective inhibitors of cytosolic phospholipase A2, they are of value in the treatment of a wide variety of clinical conditions.
Inflammatory disorders which may be treated by inhibition of cytosolic cPLA2 include such conditions as arthritis, psoriasis, asthma, inflammatory bowel disease, gout, trauma-induced inflammation such as spinal cord injury, Alzheimer""s Disease, cerebral ischemia, chronic skin inflammation, shock, damage to skin resulting from exposure to ultraviolet light or burns, allergic rhinitis, acute pancreatitis, and the like.
The compounds of the present invention have also been found to be very stable towards keto-reduction. It has been shown that a reliable method to assess keto-stability of compounds is to measure the percent of such compounds remaining after incubation with erythrocyte lysates [Rady-Pentek P., et al., Eur. J. Clin. Pharmacol., 1997, 52(2): 147-153]. The assay is the following.
Male Wistar rates were anesthetized with CO2 and then blood was removed by direct cardio-puncture or through a pre-inserted jugular vein canula into syringes that were pre-rinsed with heparin. The blood was then inserted into heparanized tubes and placed on ice. The blood was centrifuges as 3000 rpm for 5 minutes to separate the plasma. The plasma was removed and an equivalent volume of sterile water was mixed with the erythrocyte fraction. This was mixed by inversion and left on ice for several minutes to lyse the erythrocytes. The erythrocyte-water mixture was then centrifuged at 3000 rpm for 5 minutes to pellet the cellular debris.
Each compound was dissolved in methanol (1 ml) to produce a 2 mM solution. From this solution, 50 xcexcl aliquot was made up to 1 ml in 50% methanol to produce a 100 xcexcM stock solution. From this solution, a dose solution was prepared by diluting 100 xcexcl to 2 ml of a 0.1 M potassium phosphate buffer (pH=7.4) to produce a 2 xcexcM final incubation dilution.
The lysate (250 xcexcl) was then aliquoted into eppendorf tubes, 6 for each compound, i.e. 0 time, 15 minutes, 60 minutes in duplicate. To these aliquots was added 200 xcexcl of the dose solution and this was preheated to 37xc2x0 C. for 2-3 minutes prior to the addition of NADPH (1 mM final concentration) to start the reactions. The reactions were terminated with the addition of either 0.5 ml or 1 ml of acetonitrile. Following centrifugation at 8000xc3x97g for 5 minutes, the supernatant was removed and stored at xe2x88x9220xc2x0 C. until analysis could proceed by quantitative LC/MS. Samples were analyzed by electrospray ionization (ESI) on a Micromass ZMD 2000(copyright) single quadrupole mass spectrometer coupled to a Shimadzu HPLC system. The percent of compound remaining following 15 minutes and 60 minutes incubation is calculated relative to the 0 time point.
Administration Modes
The compounds of formula I are usually administered in the form of pharmaceutical compositions. They can be administered by a variety of routes including oral, rectal, transdermal, subcutaneous, intravenous, intramuscular, and intranasal. The compounds are effective as both injectable and oral compositions. Such compositions are prepared in a manner well known in the pharmaceutical art and comprise at least one active compound defined by formula I and a pharmaceutically acceptable carrier.
In making the compositions employed in the present invention the active ingredient is usually mixed with an excipient, diluted by an excipient or enclosed within a carrier which can be in the form of a capsule, sachet, paper or other container. When the excipient serves as a diluent, it can be a solid, semisolid, or liquid material, which acts as a vehicle, carrier or medium for the active ingredient. Thus, the compositions can be in the form of tablets, pills, powders, lozenges, sachets, cachets, elixirs, suspensions, emulsions, solutions, syrups, aerosols (as a solid or in a liquid medium), ointments containing for example up to 10% by weight of the active compound, soft and hard gelatin capsules, suppositories, sterile injectable solutions, and sterile packaged powders.
In preparing a formulation, it may be necessary to mill the active compound to provide the appropriate particle size prior to combining with the other ingredients. If the active compound is substantially insoluble, it ordinarily is milled to a particle size of less than 200 mesh. If the active compound is substantially water soluble, the particle size is normally adjusted by milling to provide a substantially uniform distribution in the formulation, e.g. about 40 mesh.
Some examples of suitable excipients include lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, water, syrup and methyl cellulose. The formulations can additionally include: lubricating agents such as talc, magnesium stearate, and mineral oil; wetting agents; emulsifying and suspending agents; preserving agents such as methyl- and propylhydroxybenzoates; sweetening agents; and flavoring agents. The compositions of the invention can be formulated so as to provide quick sustained or delayed release of the active ingredient after administration to the patient by employing procedures known in the art.
The compositions are preferably formulated in a unit dosage form, each dosage containing from about 5 to about 100 mg, more usually about 10 to about 30 mg, of the active ingredient. The term xe2x80x9cunit dosage formxe2x80x9d refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient.
The active compound is effective over a wide dosage range. For example, dosages per day normally fall within the range of about 0.5 to about 30 mg/kg of body weight. In the treatment of adult humans, the range of about 1 to about 15 mg/kg/day, in single or divided dose, is especially preferred. However, it will be understood that the amount of the compound actually administered will be determined by a physician, in the light of the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound administered, the age, weight, and response of the individual patient, and the severity of the patient""s symptoms, and therefore the above dosage ranges are not intended to limit the scope of the invention in any way. In some instances dosage levels below the lower limit of the aforesaid range may be more than adequate, while in other cases still larger doses may be employed without causing any harmful side effect, provided that such larger doses are first divided into several smaller doses for administration throughout the day.
Method of Preparation
The compounds of the present invention can be prepared by various methods which are known in the art. Illustrative methods of preparation are provided in the reaction schemes which follow and in the Examples.
Preparation of compounds of formula I may be accomplished via one or more of the synthetic schemes which are described below. The specific examples which follow illustrate the synthesis of representative compounds of the present invention and are not to be construed as limiting the invention in sphere or scope. The methods may be adapted to variations in order to produce compounds embraced by this invention but not specifically disclosed. Further, variations of the methods to produce the same compounds in somewhat different fashion will also be evident to one skilled in the art.
Scheme A describes methods of preparing the compounds of generic formula I wherein R3 and R4 are hydrogens. Thus, the various substituted benzaldehydes may be reacted with 1,1,1-trifluoroacetone in presence of piperidine and acetic acid in a solvent such as tetrahydrofuran and the like to give the unsaturated trifluoromethylketone II. Then, subsequent conjugate additions may be performed with various cuprates or other nucleophiles to introduce the desired substituents R1 or R2. Alternatively, the various aromatic halides may be converted to the corresponding stannanes or boronates III which are then submitted to a cross-coupling with the enol triflates IV of various xcex1-ketoesters. The resulting coupling adduct V may alternatively be reduced or submitted to a conjugate addition to introduce the R2 substituent. Both resulting esters VIA and VIB are finally converted to the corresponding trifluoromethylketones by the methods known in the art. It should be noted that this last approach may also lead to compounds of generic formula 1 wherein R3 is not a hydrogen. The preparation of enol triflates IV bearing an R3 substituent different from a hydrogen is well-known by those skilled in the art.
The synthetic methods to prepare generic compounds of Formula I wherein R1 and R2 are hydrogens are outlined in Schemes B and C. Conversion of the various propionates VII to the corresponding xcex2-trifluoromethylketoesters IB was performed by using trifluoroacetic anhydride followed by an alcohol R8OH. These trifluoromethylketones may then be protected as enol triflates VII which allow the reduction of the esters to the corresponding alcohols IX. Subsequent hydrolysis of enol ethers IX may afford the unsaturated trifluoromethylketones IC which, if desired, may be submitted to a conjugate addition with various nucleophiles and provide the compounds of the generic structure I substituted at position xcex1.
Other alternative approaches are also described in Scheme B. The various propionates VII may be converted to the corresponding trifluoromethylketones IE by using the various methods known in the art. Protection of these trifluoromethylketones as enol ethers X may be followed by an epoxidation or a bromination of the double bond. The bromides XI resulting from the bromination may then react with various alcohols R20OH to afford the epoxides XII. Subsequent alcoholysis will provide compounds of the generic structure I bearing an xcex1-alkoxy substituent (IF). On the other hand, the various propionates may alternatively be oxidized to the corresponding xcex1-hydroxyesters XIII which may then be alkylated with various halides. The usual conversion of the resulting esters XIV to the trifluoromethylketones afford the compounds of generic structure IF.
When it is desired to have a compound of generic formula I wherein the R3 or R4 substituent is an amine or an amide, the synthesis may preferably be done from various substituted aminoesters of type XV, which after acylation using the conditions well known in the art, may provide the amides XVI. Subsequent conversion to the trifluoromethylketones of generic structure IG may then be performed in using the conditions known in the art. 